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K. Tsuruoka
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P1.08 - Poster Session/ Thymoma, Mesothelioma and Other Thoracic Malignancies (ID 224)
- Event: WCLC 2015
- Type: Poster
- Track: Thymoma, Mesothelioma and Other Thoracic Malignancies
- Presentations: 1
- Moderators:
- Coordinates: 9/07/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P1.08-028 - PD-L1 Expression in Neuroendocrine Tumors of the Lung (ID 2217)
09:30 - 17:00 | Author(s): K. Tsuruoka
- Abstract
Background:
The World Health Organization (WHO) classification recognizes four major types of neuroendocrine tumors of the lung: typical carcinoid, atypical carcinoid, small cell lung cancer (SCLC), and large-cell neuroendocrine carcinoma (LCNEC). These diagnostic categories have different prognostic implications and require distinct treatment strategies. The PD-1/PD-L1 pathway is a major target of anti-tumor immunotherapy. PD-L1 expression has been reported to cause local immune suppression and is considered as a predictive marker of immune checkpoint therapeutics. In order to clarify any differences in the expression of PD-L1 according to the type of neuroendocrine tumor in the lung, we investigated the expression levels of PD-L1 by immunohistochemistry in neuroendocrine tumors of the lung.
Methods:
The subjects of this study were patients who were diagnosed as having lung neuroendocrine tumors and were treated at the National Cancer Center Hospital from 1982 to 2010. A tissue microarray (TMA) made from the surgical specimens was analyzed. After the rabbit monoclonal PD-L1 antibody was validated (clone E1L3N, Cell Signaling Technology, Danvers, MA), the TMA was stained and the tumor PD-L1 expression score was calculated by a semiquantitative method (by multiplying the intensity [0–3] by the staining area [0–100%]). To determine the PD-L1 expression, 3 (1%) was used as the cutoff score.
Results:
A total of 227 patients were included in this study. The characteristics of the entire patient population were as follows; median age, 65 years (range: 19-84 years); gender, male 168 (74.0%) / female 59 (26.0%); smoking status, smokers 191 (84.1%)/non-smokers 36 (15.9%); pStage: IA 79 (34.8%)/IB 36 (15.9%)/IIA 25 (11.0%)/IIB 29 (12.8%)/IIIA 47 (20.7%)/IIIB 6 (2.6%)/IV 5 (2.2%); histology, typical carcinoid 46 (20.3%)/atypical carcinoid 6 (2.6%)/SCLC 69 (30.4%)/LCNEC 106 (46.7%). Of the 227, samples from 15 (6.6%) showed positive staining for PD-L1. The characteristics of the patients showing positive staining for PD-L1 were as follows; median age, 71 years (range: 37-84 years); gender, males 12 (7.1%)/females 3 (5.1%); smoking status, smokers 13 (6.8%)/non-smokers 2 (5.6%); pStage, IA 3 (3.8%)/IB 2 (5.6%)/IIA 2 (8.0%)/IIB 5 (17.2%)/IIIA 2 (4.3%)/IIIB 0 (0%)/IV 1 (20.0%); histology, typical carcinoid 0 (0%)/atypical carcinoid 0 (0%)/SCLC 4 (5.8%)/LCNEC 11 (10.4%). In 31 of the 69 cases of SCLC who were treated by surgery, the disease recurred; of these 31 patients who developed disease recurrence, positive expression for PD-L1 was noted in 2 patients (6.5%). Furthermore, the disease recurred in 33 of the 106 cases of LCNEC treated by surgery; of the 33, 2 (6.1%) showed expression of PD-L1.
Conclusion:
None of the tumors in the patients with typical or atypical carcinoid in our study showed expression of PD-L1. Only the tumors in 4 of the 69 patients (5.8%) with SCLC and 11 of the 106 patients (10.4%) with LCNEC showed positive staining results for PD-L1. The data suggest that drugs directed against PD-1/PD-L1 might be potentially useful in the immunotherapy of SCLC and LCNEC.
